In most current USB chargers for electronic cigarettes, some ones are straight-through type chargers, wherein such a charger is only equivalent to an adapter (i.e., a USB interface switched into an interface matching battery rods of the electronic cigarettes); some ones only comprise comparators and state indicating units (e.g., state indicator lamps) for indicating charging states, and do not include low voltage difference linear regulators for over-temperature, over-current and short-circuit protection; and some ones only adopt low voltage difference linear regulator (LDO) control, but do not include comparators and state indicating units (e.g., state indicator lamps) for indicating charging states. In use, the above three kinds of USB chargers for electronic cigarettes may generate certain hidden dangers and bring bad experience effects to users.